On Wednesday, the Islamic State of Iraq and Syria (ISIS), an evolution of Al Qaeda in Iraq, seized control of the Syrian town of Azaz from the Free Syrian Army, a rebel umbrella group favored by the United States.

Azaz is north of the battle-scarred city of Aleppo, and along one of the key resupply routes that rebels have relied on, given its proximity to the Turkish border.

The intra-rebel fighting - with jihadis on one side, so-called "moderates" on the other - illustrated that from a US perspective, the civil war in Syria is about far more than "good guy" rebels against "bad guy" regime supporters. The BBC reports today that the warring rebel factions have agreed to set aside their differences, at least for now.

"The BBC's Paul Wood, on the Syrian border with Turkey, says that under the ceasefire deal in Azaz the two rebel sides have agreed to exchange prisoners and hand back property," the BBC reports today. "It is unclear whether the ceasefire will have an impact on clashes between the groups elsewhere in the country, (Wood) says."

The overt signs of disunity among Syria's rebels comes a day before Syria's government is expected to detail the extent of its chemical weapons arsenal and the locations where the weapons are held, a reminder that questions of what foreign countries should do about Syria's war, and the risks that could take form if and when the current order is defeated, shouldn't be far from any government's mind.

Charles Lister, an analyst at IHS Janes Terrorism and Insurgency Center, has been tracking the war in Syria almost since its beginning. I touched on some of his work in this post a few days ago and he was kind enough to email some more details on his estimates about the nature and number of "operationally active" rebel fighters. He emphasizes that they're estimates and that this is not an exact science.

Jihadists – 10-12,000

Hardline Islamists – 30,000

Ikhwani Islamists – 30-40,000

Genuine moderates – 20-25,000

Kurds – 10,000

The definitions: A "Jihadist" would be someone with a similar world-view, tactics and objectives as those of Al Qaeda. These people are interested in opposing Syrian President Bashar al-Assad as a mere stepping stone to the creation of a caliphate, governed by the Islamic law they believe prevailed at the end of the prophet Mohammed's life. They're willing to achieve this end through force, and see the United States as the most powerful enemy standing in the way of their ultimate ends.

A "hardline Islamist," to Lister, is someone who shares the jihadi worldview and cooperates with them in Syria, but are committed to fighting for the cause only within Syria. The "Ikhwani" are "brothers," as in the Muslim Brotherhood; they would like to bring Islamic law to Syria, but have a generally more tolerant interpretation of what that means and are willing to pursue their ultimate goal more slowly and with less imposition of their beliefs by force.

The "moderates" are those who aren't interested in imposing their personal religious beliefs on others, and the Kurds are the ethnic-Kurds, who are often most interested in the interests and occasional nationalist aspirations of their own ethnic group.

Lister says it's hard to put Syrian insurgents in one box or another and keep them there. Rhetoric and statements of intent vary over time, stated goals do as well, and the military side of the Syrian rebellion is a shimmering landscape of alliances of convenience, falling out, and moments of reconciliation, as the fighting in recent days in the countryside north of Aleppo attests to.

"The principal conclusion to be drawn from all of this is that the real majority of the Syrian opposition is of an Islamist character of some kind. However, the line between the hardline Islamists and Ikhwani Islamists can be extremely blurry and often varies over time," he writs. "Also, many of the larger groups vary in their politico-religious nature according to where in the country they’re operating. Crucially, insurgent dynamics in Syria are constantly shifting."

One thing he firmly believes is that statements that so-called "moderates" dominate the fight against Mr. Assad, as both US Secretary of State John Kerry and influential politicians like Senator John McCain have asserted, are not accurate.

"The key point of these calculations is really just to underline that the image of the Syrian opposition being dominated by nationalist and sometimes secular groups is simply not borne out. That being said, jihadists are most certainly not a majority force either and Ikhwani Islamists do not and should not necessarily be perceived negatively at all."

His second sentence there is worth examining. That fighters support the Syrian Muslim Brotherhood does not, ipso facto, mean that they're a threat to US or other Western interests. The movement, in its various incarnations across the Arab world down the decades, has largely confined itself to local politics and power. During the brief period when Egypt's Muslim Brotherhood - the movement's flagship - was in power in Egypt until a military-backed coup against them last July, the Egyptian brothers were happy to cooperate with US security interests in the region.

While the average American might not want to live under a Muslim Brotherhood government, that is a far different thing from the movement being a security threat to the US.

Another point of Lister's that I agree with is that the sheer numbers of fighters backing a particular cause don't determine outcomes. Zeal, weaponry, and strategic intelligence are probably more important in determining outcomes. Lister writes:

"It also worth noting however that numbers are not always representative of strategic potential and on the ground impact. Despite composing the smallest component of the anti-government insurgency, jihadists have proven remarkably adept at spreading their military resources across large swathes of territory, joining battles at the pivotal moment, and exploiting their superior organizational structures to establish political control and influence over territory."

The history of the world has often been written by small, capable and deeply committed groups. Were most Russians Bolsheviks in 1916?

Lister further suggests that the US-Russia agreement on decommissioning the Syrian government's chemical weapons stockpile, a key to which was the Obama administration's promise to hold off on threatened strikes against Assad, may feed into the narrative of those rebels who support Al Qaeda.

"While the US-Russia deal is being presented by some as a key to solving the Syrian conflict, it does in fact serve to further bolster the line presented by jihadists: that the genuine moderates and their supporters in the West do not present a strong enough force to ‘win’ the conflict," he wrote to me (a few days ago, before the reported ceasefire in Azad). "Clashes in several northern and eastern provinces between jihadists and moderates in recent days suggests these tensions are coming out into the open."

The good news, if you don't share the jihadi worldview, is the movement's almost preternatural ability to alienate the civilian populations they swim among. In Iraq during the height of the insurgency there, particularly with its attacks on US forces in predominantly Sunni Arab provinces like Anbar, Al Qaeda in Iraq managed to alienate Sunni Arab populations who hated the US presence in the country, and the government they were installing. How? They started bullying local people, often killing them, for daring to disagree with their vision of he future.

Al Qaeda in Iraq managed to turn the very people they relied on for support against them, and were dramatically weakened in Iraq as a result.

Jihadis are strong in Syria now. Anyone who says otherwise is ignoring a long string of reporting from inside the conflict. But guaranteeing any future on the basis of that fact is unwise.